The present invention generally relates to pigmentation enhancing compositions for topical application on a subject's skin, and specifically, to pigmentation enhancers comprising a prostaglandin.
Skin color in humans arises from a complex series of cellular processes which are carried out within a unique population of cells called melanocytes. Melanocytes are located in the lower part of the epidermis, and their function is to synthesize a brown pigment, melanin, which protects the body from the damaging effects of ultraviolet radiation.
When skin is exposed to ultraviolet radiation, such as that contained in sunlight, melanocytes increase their synthesis of melanin. Melanin is deposited in melanosomes, which are vesicles found within the melanocytes. The melanosomes are extruded from the melanocytes and carried to the surface of the skin by keratinocytes, which internalize the melanin containing melanosomes. The end result is that the visible layers of the skin exhibit a brown color typically known as a "tan".
The darkness of the color observed in the skin is proportionate to the amount of melanin synthesized by melanocytes and transferred to the keratinocytes. By increasing natural melanogenesis, skin can be at least partially shielded from ultraviolet radiation, and tanning of the skin can be achieved without exposure of the skin to potentially damaging ultraviolet radiation.